North Korea meeting hints at imminent nuclear test

North Korean leader Kim Jong-Un has chaired a high-level meeting that discussed a looming "great turn" in military capability, state media said, fuelling expectations of an imminent nuclear test.

Kim made a "historic" speech at the ruling party's Central Military Commission meeting, attended by the heads of the army, the National Defence Commission and the strategic rocket force, the official Korean Central News Agency (KCNA) reported on Sunday.

The meeting discussed "bringing about a great turn in bolstering military capability", said KCNA, which gave no date or details of Kim's speech.

Experts and intelligence sources say the country has completed preparations for a third nuclear test which it threatened in response to tightened UN sanctions imposed for a long-range rocket launch last December.

Over the past week Pyongyang has issued a series of daily warnings threatening action over the sanctions, including a promise on Saturday of the "toughest retaliation".

Several observers in South Korea believe the nuclear test will come before Lunar New Year starts on February 10.

In his "important" speech to the military commission, Kim Jong-Un issued specific guidelines for "defending the security and sovereignty of the country", KCNA said.

It did not elaborate but said participants vowed to "thoroughly implement the military tasks set forth".

The North insists its December rocket launch was a purely scientific mission to put a satellite into orbit.

But the US and its allies, including the South, viewed it as a disguised ballistic missile test that violated UN resolutions prompted by the North's rocket launches and nuclear tests in 2006 and 2009.

Recent satellite imagery showed unusually busy activity at the northeastern nuclear test site at Punggye-ri, closely monitored by US, South Korean and Japanese intelligence since the test threat.

The North has covered the entrance to a tunnel there in an apparent attempt to block satellite monitoring, the South's Yonhap news agency has said.

On Monday South Korea and its ally the United States will start a joint naval three-day exercise seen largely as a warning to the North.